A geeky and clumsy man, Jon is the owner of Garfield and Odie. He converses with Garfield and is often the butt of his jokes. In the animated Garfield and Friends, he was frequently portrayed as being incredibly gullible when faced with unscrupulous salesmen and rather dumb in general. On The Garfield Show, however, he's portrayed as being smarter, but still a little gullible.

Jon's birthday is July 28, 1950 (or 1951), as Jon told Garfield that he was 29 years old (he would have been 30 but he was sick a year) in a December 23, 1980 strip.[4] However, in the episode "T3000" of The Garfield Show, he is described as 22.[citation needed] In the animated show Garfield and Friends, we learn that Jon has an Italian ancestor whose name was Tony Arbuccli. Some episodes of the show suggested that Jon and his pets live in Muncie, Indiana. Jon wears contact lenses, his eyes are green,[5] and his favorite music style is polka. Jon believes in God, as he is seen praying before going to bed in the April 29, 1987 strip.[6] His personal will states that he wishes to be cremated and have his ashes spread over his accordion. He can play accordion, guitar, and bongos and sing, though his singing and musical skills are far from good. Jon Arbuckle's favorite color is red, and he likes decaffeinated coffee, chocolate-chip cookies, and unleaded gasoline. According to one episode of Garfield and Friends, some of his "fun" ways to cure boredom are buying new socks, clipping his toenails, or playing "Guess the Burp" with Garfield.[7] Jon was raised on a farm and occasionally visits his mother, father, grandma, and brother Doc Boy, who live on the farm. On a few episodes of Garfield and Friends, Jon is said to have a niece (and possibly a nephew). It is never stated how he can have a niece (or nephew), since his only sibling Doc Boy is not said to be married with kids. It is possible that Doc Boy is divorced or had children out of wedlock. This theory is further supported by the fact that Doc Boy moved back to the family farm in 1983, meaning that for the first 5 years of the strip, he resided elsewhere. This possibly could have been with his now ex-wife or ex-live in girlfriend.

Jon acquired Odie when Lyman, an old friend of his (and Odie's original owner), moved in with him and Garfield. After a few years, Lyman disappeared from the strip, never to be heard from again. The book Twenty Years and Still Kicking, which marked Garfield's twentieth year, included parodies of how Lyman left, such as "Had lunch with Jimmy Hoffa and then...". Lyman does appear in an episode of The Garfield Show, during which Jon sets out to look for him. Odie goes back to Lyman, but returns to Garfield at the end.

Despite his somewhat timid and honest nature, Jon is sometimes shown to be quite assertive on Garfield And Friends. He also shows a tendency to be a miser, as Garfield mentions how Jon passes out seeing the rates on a parking meter and Jon tries to perform an appendectomy on himself to save money.

Jon was voted number one on the Best Week Ever blog's list of "The Most Depressed Comic Book Characters".[8]

Jon also dresses in snappy outfits whenever he goes out on a date. It is briefly mentioned in one strip where Jon mentions that Liz called him a "fashion emergency". In a May 2006 strip, when he asks Garfield if his tie is too big, Garfield replies "Not at all, as long as your circus friends don't object, neither do I!"[9] In a June 2006 strip, Garfield laughs at his outfit, and when Jon asks what he is laughing at, Garfield replies, "Oh, my...where to start...where to start...".[10] In a January 2002 strip, Garfield mentions that two hundred moths committed suicide after seeing Jon's wardrobe.[11] Also, on the Halloween 2014 strip, Jon was scared of a monster hiding in his closet. Garfield said not to worry because his wardrobe will kill it.[12]

In the earlier strips, Arbuckle makes his living as a cartoonist. Garfield and Friends also shows him several times as a cartoonist. His occupation is likely still that of a cartoonist on The Garfield Show, as in the episode "Family Picture" he draws a sketch of a photograph that he wants to take as Liz's birthday present. Also, in the strip from May 2, 2010, Liz tells her parents Jon is a cartoonist.[13] Jon was also seen doing his work briefly in the August 2, 2015 strip.[14]

Similarly, Garfield Minus Garfield removes all the other characters completely and simply features Jon talking to himself. Fans connected with Jon's "loneliness and desperation" and found his "crazy antics" humorous; Jim Davis himself called Dan Walsh's (the author of Garfield Minus Garfield) strips an "inspired thing to do" and said that "some of the strips work better than the originals".[15][16]

An Arbuckle Thanksgiving and An Arbuckle Christmas have taken the two holiday video specials and digitally removed Garfield and Odie, leaving Jon as the lead.